<template>
  <div class="spec-preview" @mousemove="move">
    <img :src="imgData[Pages].imgUrl" />
    <div class="event"></div>
    <div class="big">
      <img :src="imgData[Pages].imgUrl" ref="bigimg"/>
    </div>
    <div class="mask" ref="Mask"></div>
  </div>
</template>

<script>
  export default {
    name: "Zoom",
    props:['imgData','Pages'],
    methods:{
      move(event){
        let mask = document.getElementsByClassName('mask')[0]
        let left =event.offsetX - mask.offsetWidth/2;
        let top = event.offsetY - mask.offsetHeight/2;
        let bigImg = this.$refs.bigimg
        if(left <= 0) left = 0 
        if(left >= mask.offsetWidth)  left = mask.offsetWidth
        if(top <= 0) top = 0
        if(top >= mask.offsetHeight) top = mask.offsetHeight
        mask.style.top = top + 'px'
        bigImg.style.top = top  * - 2 +"px"
        mask.style.left = left + 'px'
        bigImg.style.left = left * -2 +"px" 
      } 
    }
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0px;
      left: 0px;
      z-index: 998;
      
    }

    .mask {
          width: 50%;
          height: 50%;
          background-color: rgba(0, 255, 0, 0.3);
          position: absolute;
          left: 0;
          top: 0;
          display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>